Palmitoylation of Caveolin-1 in Endothelial Cells Is Post-translational but Irreversible

摘要: Caveolin-1 is a palmitoylated protein involved in assembly of signaling molecules plasma membrane subdomains termed caveolae and intracellular cholesterol transport. Three cysteine residues the C terminus caveolin-1 are subject to palmitoylation, which not necessary for caveolar targeting caveolin-1. Protein palmitoylation post-translational reversible modification that may be regulated turn regulate conformation, association, protein-protein interactions, localization target protein. We have undertaken detailed analysis [(3)H]palmitate incorporation into aortic endothelial cells. The linkage palmitate was hydroxylamine-sensitive thus presumably thioester bond. However, contrary expectations, blocked completely by synthesis inhibitors cycloheximide puromycin. In parallel experiments show specificity, cell-specific nitric-oxide synthase unaffected these reagents. Inhibitors trafficking, brefeldin A monensin, indicating cotranslational but rather required transport from endoplasmic reticulum Golgi membrane. addition, immunophilin chaperones form complexes with caveolin-1, i.e. FK506-binding 52, cyclophilin A, 40, were because agents bind immunophilins did inhibit palmitoylation. Pulse-chase showed essentially irreversible release significant even after 24 h. These results limited newly synthesized only occurs during continuous presence on prevents subsequent repalmitoylation.